The Clinical-Translational Informatics and Biorepository Core (CTIBC) will serve as a central repository of clinical data and biological specimens, including plasma and DNA collected from patients with hemophilia A. The CTIBC will serve as a resource to coordinate collection and storage of clinical data as well as plasma and DNA to support project 3 aim 3 and project 4 aim 1 and 2. Additionally, the CTIBC will serve as a major resource for the training core as a source of clinical data linked to biological specimens that can be used by trainees and young investigators for new clinical-translational research projects in hemostasis. Having high quality prospectively collected data linked to biological samples will provide a wealth of opportunity for clinical translational research performed by trainees participating in either the KL-2 Mentored Clinical Research Scholars Program or Master of Science in Clinical Research program.